Glitter: A Gridless Variable-Width Channel Router

In the traditional approach to channel routing, terminals must be located on grid points and wire segments must be placed on grid lines. Without using the grids, we can take advantage of the two interconnection layers with variable wire width and spacing. Terminals are no longer required to be on grids, and nets may even have different wire widths. The new gridless approach which we propose is based on design rules. The objective is to minimize the routing area, while keeping the constraints of wire widths and spacing satisfied. This router is also capable of handling channels with irregular boundaries, and cyclic constraints. The algorithm has been implemented in C language, and will be integrated into our BBL (Berkeley Building-Block Layout) system.